/*
** $Id: loslib.c,v 1.40 2012/10/19 15:54:02 roberto Exp $
** Standard Operating System library
** See Copyright Notice in lua.h
*/


#include <errno.h>
#include <locale.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#define loslib_c
#define LUA_LIB

#include "lua.h"

#include "lauxlib.h"
#include "lualib.h"


/*
** list of valid conversion specifiers for the 'strftime' function
*/
#if !defined(LUA_STRFTIMEOPTIONS)

#if !defined(LUA_USE_POSIX)
#define LUA_STRFTIMEOPTIONS	{ "aAbBcdHIjmMpSUwWxXyYz%", "" }
#else
#define LUA_STRFTIMEOPTIONS \
	{ "aAbBcCdDeFgGhHIjmMnprRStTuUVwWxXyYzZ%", "" \
	"", "E", "cCxXyY",  \
	"O", "deHImMSuUVwWy" }
#endif

#endif



/*
** By default, Lua uses tmpnam except when POSIX is available, where it
** uses mkstemp.
*/
#if defined(LUA_USE_MKSTEMP)
#include <unistd.h>
#define LUA_TMPNAMBUFSIZE	32
#define lua_tmpnam(b,e) { \
	strcpy(b, "/tmp/lua_XXXXXX"); \
	e = mkstemp(b); \
	if (e != -1) close(e); \
	e = (e == -1); }

#elif !defined(lua_tmpnam)

#define LUA_TMPNAMBUFSIZE	L_tmpnam
#define lua_tmpnam(b,e)		{ e = (tmpnam(b) == NULL); }

#endif


/*
** By default, Lua uses gmtime/localtime, except when POSIX is available,
** where it uses gmtime_r/localtime_r
*/
#if defined(LUA_USE_GMTIME_R)

#define l_gmtime(t,r)		gmtime_r(t,r)
#define l_localtime(t,r)	localtime_r(t,r)

#elif !defined(l_gmtime)

#define l_gmtime(t,r)		((void)r, gmtime(t))
#define l_localtime(t,r)  	((void)r, localtime(t))

#endif



static int os_execute (lua_State *L) {
	const char *cmd = luaL_optstring(L, 1, NULL);
	int stat = system(cmd);
	if (cmd != NULL)
		return luaL_execresult(L, stat);
	else {
		lua_pushboolean(L, stat);  /* true if there is a shell */
		return 1;
	}
}


static int os_remove (lua_State *L) {
	const char *filename = luaL_checkstring(L, 1);
	return luaL_fileresult(L, remove(filename) == 0, filename);
}


static int os_rename (lua_State *L) {
	const char *fromname = luaL_checkstring(L, 1);
	const char *toname = luaL_checkstring(L, 2);
	return luaL_fileresult(L, rename(fromname, toname) == 0, NULL);
}


static int os_tmpname (lua_State *L) {
	char buff[LUA_TMPNAMBUFSIZE];
	int err;
	lua_tmpnam(buff, err);
	if (err)
		return luaL_error(L, "unable to generate a unique filename");
	lua_pushstring(L, buff);
	return 1;
}


static int os_getenv (lua_State *L) {
	lua_pushstring(L, getenv(luaL_checkstring(L, 1)));  /* if NULL push nil */
	return 1;
}


static int os_clock (lua_State *L) {
	lua_pushnumber(L, ((lua_Number)clock())/(lua_Number)CLOCKS_PER_SEC);
	return 1;
}


/*
** {======================================================
** Time/Date operations
** { year=%Y, month=%m, day=%d, hour=%H, min=%M, sec=%S,
**   wday=%w+1, yday=%j, isdst=? }
** =======================================================
*/

static void setfield (lua_State *L, const char *key, int value) {
	lua_pushinteger(L, value);
	lua_setfield(L, -2, key);
}

static void setboolfield (lua_State *L, const char *key, int value) {
	if (value < 0)  /* undefined? */
		return;  /* does not set field */
	lua_pushboolean(L, value);
	lua_setfield(L, -2, key);
}

static int getboolfield (lua_State *L, const char *key) {
	int res;
	lua_getfield(L, -1, key);
	res = lua_isnil(L, -1) ? -1 : lua_toboolean(L, -1);
	lua_pop(L, 1);
	return res;
}


static int getfield (lua_State *L, const char *key, int d) {
	int res, isnum;
	lua_getfield(L, -1, key);
	res = (int)lua_tointegerx(L, -1, &isnum);
	if (!isnum) {
		if (d < 0)
			return luaL_error(L, "field " LUA_QS " missing in date table", key);
		res = d;
	}
	lua_pop(L, 1);
	return res;
}


static const char *checkoption (lua_State *L, const char *conv, char *buff) {
	static const char *const options[] = LUA_STRFTIMEOPTIONS;
	unsigned int i;
	for (i = 0; i < sizeof(options)/sizeof(options[0]); i += 2) {
		if (*conv != '\0' && strchr(options[i], *conv) != NULL) {
			buff[1] = *conv;
			if (*options[i + 1] == '\0') {  /* one-char conversion specifier? */
				buff[2] = '\0';  /* end buffer */
				return conv + 1;
			}
			else if (*(conv + 1) != '\0' &&
				strchr(options[i + 1], *(conv + 1)) != NULL) {
					buff[2] = *(conv + 1);  /* valid two-char conversion specifier */
					buff[3] = '\0';  /* end buffer */
					return conv + 2;
			}
		}
	}
	luaL_argerror(L, 1,
		lua_pushfstring(L, "invalid conversion specifier '%%%s'", conv));
	return conv;  /* to avoid warnings */
}


static int os_date (lua_State *L) {
	const char *s = luaL_optstring(L, 1, "%c");
	time_t t = luaL_opt(L, (time_t)luaL_checknumber, 2, time(NULL));
	struct tm tmr, *stm;
	if (*s == '!') {  /* UTC? */
		stm = l_gmtime(&t, &tmr);
		s++;  /* skip `!' */
	}
	else
		stm = l_localtime(&t, &tmr);
	if (stm == NULL)  /* invalid date? */
		lua_pushnil(L);
	else if (strcmp(s, "*t") == 0) {
		lua_createtable(L, 0, 9);  /* 9 = number of fields */
		setfield(L, "sec", stm->tm_sec);
		setfield(L, "min", stm->tm_min);
		setfield(L, "hour", stm->tm_hour);
		setfield(L, "day", stm->tm_mday);
		setfield(L, "month", stm->tm_mon+1);
		setfield(L, "year", stm->tm_year+1900);
		setfield(L, "wday", stm->tm_wday+1);
		setfield(L, "yday", stm->tm_yday+1);
		setboolfield(L, "isdst", stm->tm_isdst);
	}
	else {
		char cc[4];
		luaL_Buffer b;
		cc[0] = '%';
		luaL_buffinit(L, &b);
		while (*s) {
			if (*s != '%')  /* no conversion specifier? */
				luaL_addchar(&b, *s++);
			else {
				size_t reslen;
				char buff[200];  /* should be big enough for any conversion result */
				s = checkoption(L, s + 1, cc);
				reslen = strftime(buff, sizeof(buff), cc, stm);
				luaL_addlstring(&b, buff, reslen);
			}
		}
		luaL_pushresult(&b);
	}
	return 1;
}


static int os_time (lua_State *L) {
	time_t t;
	if (lua_isnoneornil(L, 1))  /* called without args? */
		t = time(NULL);  /* get current time */
	else {
		struct tm ts;
		luaL_checktype(L, 1, LUA_TTABLE);
		lua_settop(L, 1);  /* make sure table is at the top */
		ts.tm_sec = getfield(L, "sec", 0);
		ts.tm_min = getfield(L, "min", 0);
		ts.tm_hour = getfield(L, "hour", 12);
		ts.tm_mday = getfield(L, "day", -1);
		ts.tm_mon = getfield(L, "month", -1) - 1;
		ts.tm_year = getfield(L, "year", -1) - 1900;
		ts.tm_isdst = getboolfield(L, "isdst");
		t = mktime(&ts);
	}
	if (t == (time_t)(-1))
		lua_pushnil(L);
	else
		lua_pushnumber(L, (lua_Number)t);
	return 1;
}


static int os_difftime (lua_State *L) {
	lua_pushnumber(L, difftime((time_t)(luaL_checknumber(L, 1)),
		(time_t)(luaL_optnumber(L, 2, 0))));
	return 1;
}

/* }====================================================== */


static int os_setlocale (lua_State *L) {
	static const int cat[] = {LC_ALL, LC_COLLATE, LC_CTYPE, LC_MONETARY,
		LC_NUMERIC, LC_TIME};
	static const char *const catnames[] = {"all", "collate", "ctype", "monetary",
		"numeric", "time", NULL};
	const char *l = luaL_optstring(L, 1, NULL);
	int op = luaL_checkoption(L, 2, "all", catnames);
	lua_pushstring(L, setlocale(cat[op], l));
	return 1;
}


static int os_exit (lua_State *L) {
	int status;
	if (lua_isboolean(L, 1))
		status = (lua_toboolean(L, 1) ? EXIT_SUCCESS : EXIT_FAILURE);
	else
		status = luaL_optint(L, 1, EXIT_SUCCESS);
	if (lua_toboolean(L, 2))
		lua_close(L);
	if (L) exit(status);  /* 'if' to avoid warnings for unreachable 'return' */
	return 0;
}


static const luaL_Reg syslib[] = {
	{"clock",     os_clock},
	{"date",      os_date},
	{"difftime",  os_difftime},
	{"execute",   os_execute},
	{"exit",      os_exit},
	{"getenv",    os_getenv},
	{"remove",    os_remove},
	{"rename",    os_rename},
	{"setlocale", os_setlocale},
	{"time",      os_time},
	{"tmpname",   os_tmpname},
	{NULL, NULL}
};

/* }====================================================== */



LUAMOD_API int luaopen_os (lua_State *L) {
	luaL_newlib(L, syslib);
	return 1;
}

